/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.lvyh.lightframe.tracer.core.context;

import com.alibaba.ttl.TransmittableThreadLocal;
import com.lvyh.lightframe.tracer.core.SimpleSpan;

import java.util.EmptyStackException;

public class AsyncSimpleThreadLocalTraceContext implements SimpleTraceContext {

    private final ThreadLocal<SimpleSpan> threadLocal = new TransmittableThreadLocal<SimpleSpan>();

    @Override
    public void add(SimpleSpan span) {
        if (span == null) {
            return;
        }
        threadLocal.set(span);
    }

    @Override
    public SimpleSpan getCurrentSpan() throws EmptyStackException {
        if (this.isEmpty()) {
            return null;
        }
        return threadLocal.get();
    }

    @Override
    public SimpleSpan pop() throws EmptyStackException {
        if (this.isEmpty()) {
            return null;
        }
        SimpleSpan simpleSpan = threadLocal.get();
        this.remove();
        return simpleSpan;
    }


    @Override
    public boolean isEmpty() {
        SimpleSpan simpleSpan = threadLocal.get();
        return simpleSpan == null;
    }

    @Override
    public void remove() {
        threadLocal.remove();
    }
}
